Elite golfers soften their arms as to let lower body twist before club head impact the ball, so the intent of this study was to find out the sequential movement of down swing and its affection on the club-head velocity. The contribution of achieving maximum club head velocity is the result of a culmination of forces origination at the feet. The time between the maximum vertical force on back and front foot named ”action phase”, on front foot and impact named ”reaction phase”. The start time between latissimus dorsi and pectoralis major contraction named ”time difference of contraction”. Two separate force plates, club head speed meter, EMG and an artificial swing mate on force plate were arranged in laboratory. Samples of vertical force were collected with 1000 Hz rate in Kistler system, speed meter (m/sec) was put on the neck of club head, and the muscles activity data with 1000 Hz rate in Bio-Pac system and AcqKnowledge software were obtained from electrode detectors on latissimus dorsi and pectoralis major. Three elite golfers from national team members and four beginners were tested and named A group, B group. We found action phase of A group was 0.250±0.087sec and of B was 0.478±0.290sec, reaction phase of A group was 0.058±0.01 sec and of B was 0.049±0.25sec sec, time difference of contraction of A was 0.448±0.18 sec and of B was0.691±0.370sec sec and club head speed of A was 44.83± 1.14 ni/sec and of B was 37.27± 3.80m/sec. Moreover, there were 78 times of B group to play the un- correct sequential movement during down swing which caused the contraction time of pectoralis major prior to latissimus dorsi and reduce the club head speed to 28.74±2.02 m/sec. The T test of two group shown the significant difference on all factors but action phase of B group (.06), and the correlation test of A group shown that action phase, reaction phase, and time difference of contraction were most significant relation with club head speed(p＜.01). It shown that the correct sequential movement could increase the club head speed during golf down swing.