光电效应是光和物质相互作用的最基本过程之一.一般地，光电效应的讲解是基于爱因斯坦的光电效应公式，是从能量的角度讲解光 电子发射.本文提出一种从时间演化角度讲解光电效应的方法，揭示光电子在任意时刻吸收任意能量的光子，但不同时刻的量子跃迁 振幅相互干涉，时间演化完成后不符合爱因斯坦光电效应公式的事件恰好干涉相消，而符合光电效应公式的事件干涉加强.文章还将 这一理解与费曼路径积分理论相结合，并指出其关联性.有了从时间演化角度对光电效应的理解，可以引导学生设计时域杨氏双缝干 涉实验.

The photoelectric effect is fundamental in laser-matter interaction. Generally, students are taught by introducing the Einstein’s photoelectric-effect equation. In this paper, we propose to teach the photoelectric effect in a time-resolved perspective. According to the time-dependent perturbation theory, the electron may absorb random photons at any time, and the transitions at different moments interfere each other, resulting in the ultimate photoelectron within the expectation of Einstein’s photoelectric-effect equation. The similarity about the time-resolved photoelectric effect and Feynman path integral is analyzed. Students are suggested to conceive a strategy to observed the double-time-slit interference by using two laser pulses.