The invention discloses a preparation method and application of a Ti-MWW molecular sieve. According to the invention, secondary dry-gel conversion is adopted to prepare the Ti-MWW molecular sieve. The preparation method comprises the following steps: firstly, preparing a B-MWW carrier firstly; placing a silicon and boron mixed dry adhesive in piperidine steam for crystallizing; adding titanium in a hydrothermal process and preparing the Ti-MWW. By adopting the secondary dry-gel conversion, the prepared Ti-MWW has higher activity more than that of prepared Ti-MWW from one-step dry-gel conversion, and has comparative activity compared with Ti-MWW prepared from traditional secondary synthesis; meanwhile, the catalyst yield is high, the use mount of boric acid in the first step of the preparation process of B-MWW is reduced by almost 90 percent than that of the traditional method, and the use amount of the template piperidine is only half of the use amount of the traditional method. According to the invention, the utilization rate of the raw materials is high, the environmental load is small, and the preparation method is help to industrial production and application.