The ideal plant architecture is a new strategy for super high yield breeding of rice. Tiller angle is an important plant architecture character of rice. A reasonable tiller angle is a key factor for the ideal plant architecture and achieving high-yield breeding. Molecular design breeding is the most potential new direction of crop breeding in the future. The development of accurate and efficient functional molecular markers of target trait genes is crucial for molecular design breeding. The TAC1 (Tiller Angle Controlling) gene is the primary gene that regulates tiller angle in rice. This gene can be used to improve the compact plant architecture of indica and japonica rice varieties. The SNP variation from A to G at the fourth intron 3′ splicing point in TAC1 changes plant architecture. Based on the SNP variation, PM-TAC1 was successfully developed as a fluorescent functional molecular marker, via the penta-primer amplification refractory mutation system. Ninety-three rice materials were genotyped using this marker, and the marker was effectively used in rice plant architecture breeding. The successful development of this marker will contribute to the molecular breeding of rice plant architecture.