A novel algorithm of designing root-raised cosine (RRC) filters for data transmission application is presented. This algorithm is based on optimal equiripple design technique and the linear equations obtained from adjacent channel interference (ACI) and inter-symbol interference (ISI) constraints. Results indicate that the proposed algorithm can reduce ACI, ISI and signal-distortion. Furthermore, it is especially favorable for high-order filter designs since it avoids the numerical ill-conditioning problems.