Assessing development level of ICT in education objectively plays a very important role in measuring ICT in school totally, positioning the stage of ICT in school accurately and allocating ICT resources rationally. Considering level of ICT in school reflected by ICT equipment rate and application of ICT in instruction and learning, Readiness index of ICT in primary and secondary schools is proposed to assess ICT in education in the paper. Firstly, domestic and foreign related research are analyzed, and readiness index of ICT in schools is illustrated. Secondly, readiness indicators system of ICT in schools are constructed from input, configuration and application effect, including. Thirdly, Analytic Hierarchy Process （ AHP ） is used to determine indicators weight, geometric mean and simple linear weighted are used to measure indicators, and then readiness index of ICT in education is calculated by method of production function. Then, taking a secondary school in Shanghai for example, method to calculate readiness index of ICT in education is application analyzed, results preliminary confirmed that this readiness index can reflect ICT in school accurately and objectively, which supports decisions about development and application of ICT in education. Finally, this research supporting decisions about development and application of ICT in education from school, region and national is summarized, several questions should be further studied, including indicators optimization, sample data capturing and application of readiness index, and also next research work is concluded.