The invention discloses a detection method for the photochemistry activity of the rutile type titanium dioxide, comprising following steps: activating the rutile type titanium dioxide through the heat treatment; adding the activated titanium dioxide into the paint raw material, then adding potassium bichromate, dispersing at high speed, obtaining the paint; coating the dispersed paint film on a scraper, obtaining a paint film; drying the prepared paint film, measuring the glossiness of the paint film by a glossmeter; after the dried paint film is aged, measuring the glossiness of the paint film, calculating the gloss reduction of the paint film by the glossiness of paint film measured twice.