The invention relates to a catalytic cracking oil slurry solid-removing agent and a preparation method thereof. The catalytic cracking oil slurry solid-removing agent comprises the following components in percentage by weight: 30-50% of a solid-removing main agent adopting a structural formula (I), 5-10% of a gel breaker, 5-10% of a synergist and 30-50% of a solvent. The catalytic cracking oil slurry solid-removing agent is an oil-soluble product, so that the catalytic cracking oil slurry solid-removing agent can directly act on an oil phase; the catalytic cracking oil slurry solid-removing agent is low in using amount, quick in action and simple in method; the catalytic cracking oil slurry solid-removing agent can efficiently remove catalyst powder from a catalytic cracking oil slurry, sothat significant economic benefits are increased for an oil refining enterprise.