The primary focus of this study was to investigate a series of novel motors and pumps,based on a new type of structure called double-stator.The double-stator structure can be used as pump or motor just based on the application requirements.A certain amount of pumps or motors can be formed in one shell,and these sub-pumps or sub-motors can work alone or be combined without influence on each other.So this kind of double-stator pump(motor) is called a multi-pump(multi-motor).Through the analysis of multifarious connection modes of the double-acting double-stator multi-pumps and multi-motors,the mathematical expressions of the output flow rate and the rotational speed are acquired.The results indicate that a quantity of different flow rates can be provided by one fixed-displacement multi-pump under the condition of unalterable driven speed by electromotor.Likewise,when supplied by settled input flow,without complex variable mechanism,the functions of double-speed,multiple-speed,and even differential connection can be obtained by employing the use of a double-stator multi-motor.The novel hydraulic transmission is made of such a double-stator multi-pump and multi-motor,and has broad application prospects. The primary focus of this study was to investigate a series of novel motors and pumps, based on a new type of structure called double-stator. The double-stator structure can be used as a pump or motor just based on the application requirements. Certain amount of pumps or motors can be formed in one shell, and these sub-pumps or sub-motors can work alone or be combined without influence on each other. This kind of double-stator pump (motor) is called a multi-pump Thrrough the analysis of multifarious connection modes of the double-acting double-stator multi-pumps and multi-motors, the mathematical expressions of the output flow rate and the rotational speed are acquired. results that indicates a a quantity of different flow rates can be provided by one fixed-displacement multi-pump under the condition of unalterable driven speed by electromotor. Thumbwise, when supplied by settled input flow, without complex variable mechanism, the functions of double-speed, multiple-speed, and even di fferential connection can be obtained by employing the use of a double-stator multi-motor. The novel hydraulic transmission is made of such a double-stator multi-pump and multi-motor, and has broad application prospects.