First of all, introduce the “ultrasonic knife and picosecond”. 1, ultrasound knife: some people describe doing ultrasound knife like “barbecue”, it heats the limit of temperature up to 65 ~ 70 ℃, the effect on the subcutaneous produce a ‘thermal coagulation point’, causing minor subcutaneous damage, prompting collagen proliferation and denaturation contraction. It has three treatment heads: 1.5mm focused on the superficial dermis to improve wrinkles, 3.0mm focused on the deep dermis to tighten the skin, and 4.5mm focused on the fascia layer to play a lifting role. In addition, ultrasonic knife in China, the State Food and Drug Administration has never been approved. 2, picosecond: Picosecond mainly targets the blasting of melanin cells, and plays the effect of skin rejuvenation and skin tightening through heat energy. It is suitable for pigmentation, but other skin problems are not too prominent, to achieve the effect of whitening and light spot. Secondly, what problems do you want to solve? Through the introduction of ultrasonic knife and picosecond above, we know that there are differences in the problems they solve: ultrasonic knife mainly lifts and tightens the skin, while picosecond mainly functions to remove spots and rejuvenate the skin. If you simply want to get rid of spots, it is enough to do picosecond, so you don’t need to consider “which one to do first, ultrasonic knife or picosecond? You don’t have to think about such questions. If you want to do both ultrasonic knife and picosecond, clinically, you should do ultrasonic knife first and then picosecond, because there is a recovery period for picosecond, and it may take several treatments. Also, picosecond is not a “one-size-fits-all” solution. What does that mean? Picosecond targets melanocytes, so it is only effective for spots caused by melanocytes, such as freckles, age spots, coffee spots, brown spots, nevus of Ota and so on. However, it is not suitable for red spots such as red spider nevus or hemangioma with picosecond laser. If you just want to remove spots and rejuvenate your skin, you can choose with your actual situation, it does not have to be picosecond, there are many other choices.