Abstract: The hydrogen index IH and the original hydrogen index IHo, the most important parameters in the rock pyrolysis test, are critical indicators for measuring the hydrocarbon generation potential of source rocks. In view of the shortcomings of the existing IHo model, an improved model was proposed to deliver a higher coincidence between the calculated results and the measured values. Moreover, the quantitative model of parameters such as carbon recovery coefficient, original organic carbon content, convertible carbon content, convertible carbon percentage, conversion ratio, degradation ratio, hydrocarbon generation ratio, and original organic porosity, was derived. Based on the rock pyrolysis and TOC data of 1249 groups of rock samples in 7 basins around the world, the key parameters of IHo model for four types of source rocks with Type I, IIa, IIb and III organic matters were obtained by fitting, and the template that the parameters (e.g. hydrocarbon generation potential, carbon recovery coefficient, conversion ratio, degradation ratio, hydrocarbon generation ratio, and original organic porosity) change with Tmax was established for four types of source rocks. These models and templates supplement the existing quantitative research tools for effective source rocks, and are expected to promote the development of oil and gas resources evaluation technology.