The invention provides green composite cement and a preparation method thereof. Calcium oxide is produced by white mud generated by a paper-making factory, a certain quantity of activated lead zinc iron micro-powder, cement clinker and setting time regulators are doped according to the proportion of 20%:(55-60%):20%:(0-5%) to produce the novel green composite cement, waste resource utilization is realized, energy is saved, manufacturing cost is reduced, and the green composite cement has important scientific, technological and social significance and economic values.