A biomechanics analyzing system and a biomechanics computerized analyzing method for analyzing an organism when the organism performs an act by himself are provided. The biomechanics analyzing system includes an accelerometer, a low-pass filter, and a processing unit. The accelerometer is configured to be disposed on a surface of a muscle of the organism and is further configured to detect an acceleration signal. The low-pass filter is connected to the accelerometer and is configured for receiving the acceleration signal from the accelerometer and filtering the acceleration signal to produce a low-frequency signal. The processing unit is connected to the low-pass filter, and is configured for receiving the low-frequency signal from the low-pass filter and analyzing a frequency of a motion state of the organism according to the low-frequency signal.