The paper deals with a novel high-precision time interval measurement method, in which a single measurement can reach subpicosecond (rms<1 ps) precision. It introduces the principle and the realization of the high precision time interval measurement method based on SAW filter excitation. The method is based on the fact that two SAW filters excited by two short pulses can generate well-defined finite signals with highly suppressed spectra outside a narrow frequency band. If the responses to two excitations are sampled at clock ticks, they can be precisely reconstructed from a finite number of samples and then compared so as to determine the time interval between the two excitations. The main reasons for the measurement uncertainty of this method are the deterministic error and the random error. The deterministic error propagation model for the measurement method is deduced in detail. The time-interpolation error caused by deterministic effects has been analyzed in the paper. It has been shown that the mean square of the interpolation error is limited by the upper bound which is proportional to the relative energy of aliasing distortion and inversely proportional to the square of the filter center frequency.%提出了一种新的高精度时间间隔测量方法，单次测量可以达到亚皮秒(rms<1 ps)量级测量精度。简单介绍了这种基于声表面波技术的高精度时间间隔测量方法原理与系统组成，阐述了影响系统测量精度的主要因素，分为系统误差和随机误差。针对系统误差进行详细分析，给出其对测量精度的影响范围。通过理论分析，得到决定系统误差大小的重要参数，从而合理设计参数来降低系统误差对测量精度的影响。
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