Abstract: As pressure recovery will take a long shut-in time for wells in low porosity and low permeability gas reservoir,well test method which is used to obtain formation parameters is not appropriate.A combination of traditional and modern method is used in this paper to study production decline rule of wells in H3 Gas Reservoir of Daniudi Oil Field.This production decline analysis method is based on Arps production decline method,introducing the concept of Blasingame normalized production,material balance time and the adjusted time,turning variable pressure/production data into equivalent constant pressure system.Using Fetkovich's production decline standard chart to carry on the fitting,the matching point data is calculated to get formation parameters and used for Arps method to forecast the production.This method turning variable pressure/production data into equivalent constant pressure system improves the reliability of the production decline analysis,having the advantages of simple operation of Fetkovich production decline method,It also effectively utilized the gas well production data of unstable flow period(transient flow period)to calculate the reservoir parameters.