Based upon the policy diffusion theory, this research identifies research dimensions of public policy diffusion in terms of quantitative analysis of documents, and proposes a paradigm to measure the diffusion. By taking the policies of scientific and technological achievement transformation in China as an example, the study analyzes stratified networks of external characteristics as well as the time sequence of key words during the implication of internal instruments in policy documents. This study examines the process and characteristics of policy diffusion from four dimensions （ strength, width,speed, and direction）. The research has several findings. In the policies of scientific and technological achievement transformation in China, planning policies and legal policies have high strength on diffusion and both concentrated in the frequency distributions. Compare to the planning policies, legal policies have more dimensions on diffusion width, geographically involve more regions, more durable and stable in the diffusion process of all levels. Unlike the diffusion speed of the legal policies stays relatively low and steady, the speed in the planning policies case falls sharply after reaching at its peak in a short period of time, and maintains a tendency of descending in general. Through the analyses of time sequence of key words in the financial instruments of venture capital and risk compensation tools for startups, policy diffusion appears three apparent directions, which are top-down, bottom-up and parallel. This research states that, through analyses on stratified network and key-word time sequences, it＇ s effective to reveal the process and characteristics of policy diffusion from the four research dimensions.