The invention discloses a triangular-wave altitude signal processing method and system. The method includes the specific steps that a time period to be processed is selected, and voltage values of crest and trough peaks which meet preset requirements in the time period to be processed are obtained; according to the voltage values, triangular-wave peak characteristic values and edge characteristic values are generated; according to the characteristic values, triangular-wave peak time and a liquid-level-meter peak height value corresponding to the triangular-wave peak time are obtained; according to the peak time and the peak height value, liquid-level height values of ends of the time period are calculated. According to the triangular-wave altitude signal processing method and system, collected peak and trough values are screened to meet needed accuracy requirements, then, the values which meet the requirements are subjected to subsequent processing, relatively accurate height values can be obtained, errors are small, the credibility of data is relatively high, no manual work is needed to conduct determination and calibration, and manpower resources are saved.