To realize the distributed detection function of a sounding rocket platform and to improve its detection agility and precision, a pneumatic release device with a convenient load module, highly reliable clamping, high release precision, and a continuous wide-range thrust was designed. First, the entire design scheme was designed with the features of trapezoidal separating configuration, a size fine-tuning function, and non-uniform releasing contact areas. Second, an optimized, low-cost detailed design was provided by using the shelf products of thin type cylinders. Then, based on the entire design scheme, a releasing function test of the thin cylinder ground-based prototype was accomplished. Finally, a reference value (5 mm) that is suitable for engineering assembly with the required release precision is obtained. The results indicate that the pneumatic release device can work normally with actual air pressure, and its release precision is better than 0.05°. It can satisfy the requirements of the distributed detection function of sounding rocket platforms, and its release precision can be improved by considering actual different cases.