In order to further improve the thermal expansion coefficient of LaMgAl11O19, LaMgAl11O19 with Sr2+ doped is designed to increase the density of oxygen vacancies, and the effect of doping Sr2+ to hardness and toughness was studied. SrxLa1-xMgAl11O19-0.5x pellets were synthesized by hot-pressing (1500°C, 40MPa). The relative density of LaMgAl11O19 reaches 97.68%. The hardness of LaMgAl11O19 is about 25.47GPa and the fracture toughness is 11.3 MPa•m1/2. The thermal expansion coefficient of LaMgAl11O19 was 8.71×10-6K-1, and Sr0.6La0.4MgAl11O18.7 was 8.95×10-6K-1. The results showed hot-pressure sintering could synthesize dense SrxLa1-xMgAl11O19-0.5x with magnetoplumbite structure. Sr2+ doping could increase the thermal expansion coefficient of LaMgAl11O19.