Several signal synchronization problems based on piezoelectric ceramics (PZT) of laser interference system have been described. Firstly, as for D/A of collection card to drive PZT and A/D high speed sampling, two methods are described respectively. One is using Visual C++ by improved software algorithm to implement synchronization and the other combines hardware and software to implement synchronization. And PZT linear characteristics curve is drawn to comprise pros and cons of two synchronization method. Secondly, for common collection card with several channels is asynchronous, and the lower sampling frequency is, the larger the errors is, by the way of increasing Analog Input (IA) channels, symmetric layout sampling channels are used to eliminate errors because of sampling interval, which can realize high precision adjacent quadrant phase difference. Meanwhile, it has some effect on filter. Lastly, moving average is analyzed by spectrum characteristic. Experimental results indicate that the way of synchronism will improve the system measurement precision of phase, and filtering algorithm can filter background noise caused by light intensity and optical electronic devices.