By using the waveform measurements and the least square method, the top, the base, the middle value, the amplitude, the frequency of triangle waveform, and the slope of edge, the edge linearity of waveforms are evaluated precisely. The evaluation courses and some technical problems are discussed in detail, the uncertainty analysis both of the amplitude value and frequency value are presented. Some test results have proved the effectiveness and practicability of the method. It could be applied to the characteristics and performance evaluation of triangle waveform generators.