In the testing Cloud platform, there exist too many testing tasks waiting for scheduling at the same time. How to design scheduling strategy is really a challenging problem. In this paper, we firstly analyze the relationship between the testing tasks and establish the task relationship model. Based on these analyses, we propose a dynamic task scheduling strategy using genetic algorithm, which not only ensures to get the least execution time but also guarantee load balance. The dynamic strategy based on genetic algorithm is being compared with traditional static genetic algorithm on cloudsim. The experimental result shows the high the effectiveness of the proposed strategy.