Abstract: Laser diode pumped microchip lasers passively Q-switched by Cr4+:YAG, with high repetition rate, short pulse width and high peak power, have important applications in optical communication, lidar, remote sensing, nonlinear frequency conversion, laser micro-processing and so on. However, in these lasers, the output stability is poor and the repetition rate of output laser cannot be changed widely. This will restrict the applications of these lasers in fluorescence analysis of aerosols or ranging, space optical communication. In the experiment, output pulses with continuously tunable repetition rate from 2 kHz to 28 kHz and stable oscillation were obtained in the laser diode pumped microchip laser passively Q-switched by Cr4+:YAG. In the stability of single pulse energy from 2 kHz to 28 kHz was less than 2.50%. Stable 2.431 ns pulse at 20 kHz with single pulse energy of 17.6 J and extinction ratio of 252:1 and with amplitude instability of 4.00% and frequency instability of 2.40% was obtained. This laser diode pumped microchip laser passively Q-switched by Cr4+:YAG with wide continuously tunable repetition rate and stable oscillation will have broad application prospects.