Measurement of laminar burning velocities and Markstein lengths were made for the diethyl ether-air mixtures at different equivalence ratios, initial temperatures, and pressures by using spherically propagating flame and schlieren photography method. The results show that the stretched flame propagation speeds, the unstretched flame propagation speeds, the stretched laminar burning velocities, the stretched mass burning velocities, and the unstretched laminar burning velocities increase with the increase of the initial temperature. Although the Markstein lengths decreases with the increase of the initial temperature. The stretched flame propagation speeds, the unstretched flame propagation speeds, the stretched laminar burning velocities, the stretched mass burning velocities, the unstretched laminar burning velocities and the Markstein lengths are decreased with the increase of the initial pressure, and the Markstein lengths are also decreased with the increase of the equivalence ratio. On the basis of the experimental data, a correlation is obtained for the unstretched laminar burning velocity versus the initial temperature and pressure over wide range of equivalence ratios.