The improper morphology of the handle and non-uniform stress distribution during the use of rice transplanters will cause hand injury. To make operators feel more comfortable when they hold the handle of rice transplanters, the ANSYS finite element analysis and JACK human simulation were made to find shortcomings of the original handle parts of rice transplanters. A handle that fitted the hand and grip force was designed, and the designed model was 3D-printed and tested. The results showed that compared with the original handle, the modified one had a larger stress area, with improved stress concentration. Moreover, the modified handle improved the tense postures of hand muscles and angles between finger joints, and the steering and throttle levers were adjusted so that they were in the rotation range of the hand. This study provides a theoretical basis for the improvement of handle components of rice transplanters.