The invention relates to the field of well drilling of oil industry and specifically relates to an accelerating agent for a drilling fluid, a water-based drilling fluid and an application thereof. The accelerating agent contains sulfonated polyglycerol long-chain fatty acid, fatty alcohol-polyoxyethylene ether, alcohol ether carboxylate, glycidyl ether and alkylphenol polyoxyethylene ether, wherein the mass ratio of sulfonated polyglycerol long-chain fatty acid to fatty alcohol-polyoxyethylene ether to alcohol ether carboxylate to glycidyl ether to alkylphenol polyoxyethylene ether is 100:(1-10): (0.5-10):(1-10):(1-10). The accelerating agent provided by the invention is capable of lubricating a drill bit and a drilling tool, preventing drilling cuttings from mutually gathering, reducing friction and increasing mechanical drilling speed.