The objective of this research was to identify biomechanical differences of the striking arm of forehand and backhand service skills and the two researchers used the descriptive method depending on video analysis technique of high speed for the skill through the Simi Motor program. The research sample consisted of 5 players classified as the best 10 players at the level of the Arab Republic of Egypt under 19 years.             The two researchers used a statistical program (SPSS) where 10 trials of forehand service and 10 trials of backhand service were treated.             The two researchers concluded that the squash player benefits from the right shoulder velocity of the striking arm during the moment of hitting and the horizontal and vertical velocities of the ball in the backhand service are faster than those in the forehand service. It was recommended that mechanical characteristics achieved by the two researchers enable to determine the effectiveness of the skill performance of backhand and forehand services in squash players in addition to considering giving exercises to improve strength differentiated by speed for the two arms.