A series of Li2Mg2.95M0.05TiO6（M for Mg，Zn，Co，Ca） microwave dielectric ceramics were prepared by one-step reaction method，and the effects of doped ion on ceramic sintering behavior，composition，microstructure and microwave dielectric properties were discussed. The results showed that the main crystal phase of the obtained ceramic sample was Li2Mg3TiO6. There was a little Mg2TiO4 impurity phase when Mg2+ was doped. The ceramic doped with Ca2+ generated the phase CaTiO3 which had large dielectric constant（εr） up to 170，temperature coefficient（τf） up to +800×10-6/℃. The phase CaTiO3 coexisted with Li2Mg3TiO6 phase and formed a stable complex system. The samples mixed with Ca2+ and sintered for 6 h at 1 370 ℃ demonstrated better dielectric properties: the dielectric constant（εr） is 16.7，the quality factor（Q×f） is 83 900 GHz，and the resonant temperature coefficient（τf） is close to 0 ×10-6/℃.