Abstract: A method was proposed to analyze the distribution principle of the induced velocity varying with the jump time and radial stand position in gyroplane. A novel response model was developed based on blade element theory and momentum theory for the dynamic induced velocity and transient thrust of rotor following a rapid blade-pitch increase, and it was experimentally validated with NACA data. Then the response model was introduced into a nonlinear jump takeoff model considering the ground effect of gyroplane. The piecewise numerical solution of the jump model was got by regarding the beginning and ending time as the piecewise point. The simulation results of a small scaled jump takeoff platform show good agreement with experiment data. Finally, the rotor induced velocity distribution of the test platform was worked out with the jump takeoff model. Results show that the induced velocity is a linear then parabola time function at the same radial stand position and an approximate linear function of the radial stand position at the same time.