Abstract: Studies on cavity tuning characteristics of dual-frequency lasers can be helpful for expanding laser physics theory and sensing applications. Based on microchip Nd:YAG orthogonally polarized dual-frequency laser, several important cavity tuning characteristics of dual-frequency laser are studied, including intensity tuning, frequency difference tuning, sub resonant cavity effect and frequency difference lock-in. Experimental results and data are presented. With cavity tuning, the variation of frequency difference between two orthogonally polarized frequencies can be up to 350 kHz; when sub resonant cavities exist, the maximum variation can be up to 2 MHz; frequency difference lock-in has not been found and the minimum frequency difference is about 14 MHz.