Abstract: The affordability of natural gas price reflects the carrying capacity of natural gas users to natural gas prices, which is characterized by affordable natural gas prices.Unlike market prices, affordable natural gas prices reflect the highest prices that users are willing to pay for natural gas and rather than quantified by supply and demand.This paper introduces the researches on the energy price affordability and summarizes literatures about domestic natural gas price affordability.Then the theoretical system of natural gas price affordability is systematically combed.The farther researches and development directions are put forward, including:making intensive study on generalized affordable natural gas prices for different users; quantitative analysis on natural gas market with natural gas demand curve; natural gas price formation mechanism study based on affordability of natural gas price theory.