A new modified space marching method is presented for solving transient nonlinear inverse heat conduction problems. The new method combines the merits of space marching and function specification methods. Future temperature measurements are used in a least square manner to stabilize the calculation results. The transient surface temperature and heat flux can be accurately recovered by the method without employing iteration procedure or data smoothing technique. Three types of heat flux profiles were used to evaluate the proposed inversion method and a comparison to the classical space marching method was drawn to demonstrate the advantage of the present method. A numerical experiment is performed to investigate the influence of parameters in the method as well as to illustrate the selection of optimal parameters. The present method calculates surface temperature and heat flux values in a sequential manner therefore is suitable for on-line estimation application. (C) 2016 Published by Elsevier Ltd.