Peanut （Arachis hypogaea L.） is an important economic and oilseed crop. The red testa in peanut is associated with higher anthocyanin content， which enhances its antioxidant and anti-inflammatory properties， highlighting the commercial potential of breeding new varieties with red testa. Here， we investigated the genetic basis of red testa color using three segregation populations generated from crosses between two red-testa varieties， Zhenzhuhong 1 （ZZH1） and Zhanhong 2 （ZH2）， and one pink-testa variety， Yuhua 15 （YH15）. The F1 progeny of YH15×ZZH1 and ZH2×ZZH1 displayed red testa， while those of ZH2×YH15 had pink testa， indicating that red testa is inherited as a dominant trait in ZZH1 but as a recessive trait in ZH2. Segregation analysis in the F2 populations showed that testa color in YH15×ZZH1 controlled by a single dominant gne， while that in ZH2×YH15 was governed by a single recessive gene. In contrast， the F2 population of ZH2×ZZH1 exhibited a segregation ratio consistent with control by two genes. These results suggest that red testa can be classified into dominant and recessive types， each regulated by distinct genes. Using bulked segregant analysis （BSA） with non-segregating red- and pink-testa lines from the YH15×ZZH1 population， we mapped a major quantitative trait locus （QTL） for dominant red testa to a 0.898 Mb region on chromosome 3. This QTL exhibited LOD scores ranging from 113.18-139.16 and accounted for 95.2%-97.6% of the phenotypic variance. Furthermore， by evaluating two newly designed markers according to previously reported markers and one newly developed marker across three populations， we found that the marker Tif2.A03.126107404 was completely linked to the dominant red testa trait， while Tif1.A03.125867405 was highly linked to it. In addition， the marker Tif1.A12.117190528 showed completely linkage to the recessive red testa. These markers provide valuable tools for molecular marker-assisted breeding of red testa in peanut.