An important assumption lies behind the efficient-market hypothesis： the market is so efficient that every new information is spread to the whole market immediately, and the latter takes rational and ＂correct＂ reaction to the new information at once. The prices of the securities reach new balance at the time the news is released. However, this doesn＇t exist in reality because it takes time for the news to travel and for the market to react. In order to make improvements to the efficient-market hypothesis, and facilitate the quantitative measurement of the efficiency of the securities market, we put forward the Spring Oscillator Theory, which advances the test of the random-walk model within the frame of efficient-market hypothesis from the 1st order to the 2na order. This model expresses the weak efficient market and the sub-strong efficient market using the unified fluctuation equation. The Theory can better explain the ＂over-reaction＂, ＂under-reaction＂ and the booming and collapse of the stock market with no news