The invention discloses a new technology for exploring a preparation method for synthesizing (1-x) PMN-xPT lead-based relaxation iron electric ceramic with pure perovskite structure by taking magnesium oxide, niobium pentaoxide, lead oxide, titanium dioxide and citric acid as raw materials with a citrate grains package method. The preparation method is mainly characterized in that the citrate grains package method can completely pack niobium pentaoxide solid grains to prevent niobium from directly reacting with plumbum to generate pyrochlore structure phase. Therefore, the preparation method reduces the cost and the pollution, and is suitable for the industrial application. The name of the invention is the preparation method of (1-x) PMN-xPT ceramic (powder) material.