The branches of tradescantia fiumiensis were irradiated with carbon ions, and the initial energy of the carbon ions was 95.8 MeV/u (dose rate 4 Gy/min, dose range 0−20 Gy). A mutant line with pink leaves was obtained. The aim is to explore the mutation mechanism of the mutant with pink leaves obtained by carbon ions irradiation in tradescantia fiumiensis. pH differential method was used to evaluate the total anthocyanidin content of wild type and its mutant with pink leaves. HPLC-MS method was used to detect the anthocyanin pigmentation between wild type and its mutant with pink leaves. The total anthocyanidin content of the mutant was 18 fold than that of wild type. Seven anthocyanins were determined and identified as pelargonidin, cyaniding, petunidin, malvidin, pelargonidin-3-glucoside, peonidin-3-glucoside and cyanidin-3-O-rhamnosylglucoside in the mutant; Six anthocyanins were determined and petunidin could not be detected in wild type. The results showed that, compared with wild type, the total anthocyanidin content increased and the components of anthocyanin were also changed in the mutant.Cited