Parkinson’s disease needs to be differentiated primarily from Parkinson’s syndrome due to other causes. Parkinson’s syndrome is a broad category that includes primary Parkinson’s disease, Parkinson’s superimposed syndrome, secondary Parkinson’s syndrome, and genetic degenerative Parkinson’s syndrome. Asymmetrical signs and symptoms, resting tremor, and sensitivity to levodopa treatment mostly suggest primary Parkinson’s disease. Parkinson’s superimposed syndrome: Parkinson’s superimposed syndrome includes multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal ganglia degeneration (CBD). The presence of prominent speech and gait disturbances, postural instability, significantly higher mid-axis tone than extremities, absence of resting tremor, prominent autonomic dysfunction, and non-response or non-sustained efficacy to levodopa early in the disease suggest the possibility of Parkinson’s superimposed syndrome. Although the above clues are helpful in determining the diagnosis of Parkinson’s superimposed syndrome, it is more difficult to specify the specific subtype. In general, the presence of prominent postural hypotension or concomitant cerebellar signs is more likely to suggest multisystem atrophy. Vertical gaze palsy, especially difficulty with downward gaze, neck hyperextension, and early falls are mostly suggestive of progressive supranuclear palsy. Asymmetrical limited hypertonia, myoclonus, disuse, and heterogeneous limb phenomena mostly suggest cortical basal ganglia degeneration. 2, secondary Parkinson’s syndrome: this syndrome is caused by drugs, infection, poisoning, stroke, trauma and other clear etiology. Through careful history taking and corresponding laboratory tests, such diseases are generally easier to differentiate from primary Parkinson’s disease. Drugs are the most common cause of secondary Parkinson’s syndrome. Neuroleptics (phenothiazines and butylphenols) used to treat psychiatric disorders are the most common causative agents. It is important to note that sometimes we also use these drugs to treat non-psychiatric disorders such as vomiting, such as the application of promethazine to stop vomiting. Other drugs that can cause or worsen Parkinson’s-like symptoms include reserpine, flunarizine, metoclopramide, lithium, etc. 3, idiopathic tremor (essential tremor, ET): This disease has an insidious onset and progresses very slowly or remits for a long time. About 1/3 of patients have a family history. Tremor is the only clinical symptom, mainly manifesting as postural tremor and motor tremor, i.e. tremor easily occurs when the body holds a certain posture or does movements. The tremor often involves both limbs, and the head is also more frequently involved. The frequency of the tremor is 6 to 12 Hz, and it may increase when the body is excited or tense, and decrease or disappear when it is still. The prominent difference between this disease and Parkinson’s disease is that idiopathic tremor starts with bilateral symptoms, without motor retardation, without resting tremor, and the disease progresses very slowly, mostly with a family history, and a significant proportion of patients’ quality of life is hardly affected. 4, other: genetic degenerative Parkinson’s syndrome is often accompanied by other signs and symptoms, so it is generally not difficult to identify. For example, hepatomegaly may be accompanied by corneal pigment rings and liver function impairment. Patients with depression can present with lack of expression, slow thinking, and reduced movement, sometimes easily misdiagnosed as Parkinson’s disease, but depression is generally not accompanied by resting tremor and muscle tonicity, symmetrical onset, with significant depressed mood and lack of pleasure can be distinguished.