4 months baby big movement backward should be timely medical examination to determine the cause of the disease, physiological reasons can increase the child’s training, pathological reasons need to be rehabilitation training. 1. Physiological reasons: mainly include the child’s overweight or daily training is too little caused by the backwardness of the large movement, can be through daily control of the child’s diet, to ensure balanced nutrition, strengthen the large movement training, etc. to promote the child to catch up with children of the same age. 2. Pathological reasons: such as abnormal brain development, cerebral palsy and other diseases, can also cause the child’s large motor backwardness, at this time should actively treat the original disease, for backward large motor targeted functional training, so that the child gradually adapted to the large motor development. If your 4-month-old baby’s gross motor lagging behind, it is recommended to go to a regular hospital in time for a comprehensive evaluation to determine the cause, so as to take appropriate treatment.