Constraining proximity-based drugs, such as proteolysis targeting chimeras (PROTACs), into their bioactive conformation can significantly impact their selectivity and potency. However, traditional methods for achieving this often involve complex and time-consuming synthetic procedures. Here, we introduced an alternative approach by demonstrating DNA-templated spatially controlled PROTACs (DTACs), which leverage the programmability of nucleic acid-based self-assembly for efficient synthesis and offer precise control over inhibitors' spacing and orientation. The resulting constructs revealed distance- and orientation-dependent selectivity and degradation potency for the Cyclin D1-CDK4/6 protein complex in cancer cells. Notably, the optimal construct DTAC-V1 demonstrated unprecedented synchronous degradation of the entire Cyclin D1-CDK4/6 complex, leading to robust G1-phase cell cycle arrest and effective inhibition of cancer cell proliferation. Furthermore, in a xenograft mouse model, DTAC-V1 exhibited potent therapeutic efficacy by effectively degrading Cyclin D1-CDK4/6 and suppressing tumor growth, underscoring its potential as an anticancer agent. Overall, our findings demonstrate the feasibility of DTAC as a rapid, scalable, and modular platform for the spatial control of functional inhibitors for optimal effectiveness, making it a promising method for proximity-based therapeutics.