Mechanical properties of tomato fruits and its peduncles are vital basis in design and control of tomato harvesting robot. Tests of compression from transversal and longitudinal directions for tomato fruit of different ripening phases, and tests of bending and stretching for tomato peduncle were conducted. Test results show the tomato fruits’ capacity of resistance for compression is significant anisotropy and it reaches the peak from greenness stage to green ripening stage, and then falls rapidly with increase of maturity. These results are explained with simplified force structure. Test results of stretching and bending for tomato peduncles indicate that all peduncles break at absciss layer and peduncle bending is a better way to detach fruit for robotic tomato- harvesting.