In the paper, new composite coal water slurry is prepared by the cattle dung. This new CWS utilizes biomass waste instead of some content coal, and it shows similar property with CWS by pure coal. The co-slurrying properties and the influences of adding amount and preparation conditions of cattle dung were studied. Experiments show that: the adding cattle dung could prepare coal-water slurry with more stabilization than not, but the calorific value of biomass CWS is less than pure coal. For keeping the calorific value of biomass CWS, the dry biomass dosage can reach 7%. Through the experiment detection biomass-CWS properties, we found the best preparation conditions and the best ratio of cattle dung, coal, water and additives for co-slurrying. As the result shown, the biomass-CWS is prepared by wet process with 53% coal, 7%water and 0.6% additive. Consider fresh cattle dung having 70% water, this CWS should be prepared by wet pulping and ball milling 60mins.