Abstract:  A method for reconstructing Martian atmospheric density and wind velocity based on an entry sphere was proposed for the disadvantage of current detection methods.The sphere carries an accelerometer and a gyroscope to measure the drag acceleration and attitude.The wind velocity and density were decoupled based on the drag direction to solve the wind velocity independently，and the density was solved based on the high-precision wind velocity.The inversion algorithm error was analyzed through theoretical analysis and numerical simulation.The results show that the method can estimate the density and wind velocity of the middle and lower atmosphere effectively.The accuracy level of the transverse wind velocity and the density are less than 8% and 7%，respectively，below the height of 80km.

Key words: Martian atmosphere, entry sphere, wind velocity, atmospheric density, accelerometer