Technological progress promote the entering speed of new products into a market． In order to occu-py the market by more efficient upgrading of products，companies often choose to launch new generation prod-ucts． As the enterprises continuously introduce new generation products，new and old products will coexist for some time in a duopoly market． The paper studies the optimal timing of the improved new product and the price adjustment of old products after the introduction of the improved new product，and analyzes the relation-ship between the optimal time-to-market or the price adjustment of the old product and the coefficient of inno-vation or pricing． The result shows that: the greater the market potential of the old product and the higher the technical level，the later the optimal time-to-market of the improved new product; the higher the technical lev-el of the improved new product，the earlier the optimal time-to-market of the improved new product; the price and technology level of the product in the competitive enterprise has a negative effect on the optimal time-to-market of the improved new product; the price and technology level of the improved new product or the product in the competitive enterprise has a negative effect on the price adjustment of old products．