This Research in order to review the effect of horse rumen compost activator, with additional gamal leaves against the rate of decomposition and quality of rice husk waste compost in accordance with SNI. This research was conducted from February to July 2017. This research By using experimental method with single factor treatment design that arranged by complete randomized design (CRD) with four treatments, that is : Rice husk + horse Rumen, Rice husk + Rumen horse + Gamal leaves, Rice husk + horse Rumen, and Rice husk + EM4. Each treatment repeated three times and get twelve experimental unit. parameters observed included Physical observed (temperature, colour, smell, moisture content, particle size and the ability to binding water), chemistry observed (pH) and final compost observe (COrganik, BO, N, C/N Ratio). Results of the research showed that composting rice husk using rumen horse activator and additional gamal leaves produce compost that is appropriated by SNI (SNI 19-7030-2004),except B-Organik dan C/N ratio