In this work, we employed the in situ synthesis method to implant FeO into activated carbon (AC), in which the synthesis of the magnetic AC (MAC) was realized. Thence, Ni-doped anatase TiO (NATiO) were anchored on different addition amount of MAC to synthesize the series of Ni-TiO/MAC photocatalysts. The chemical compositions and physical properties of these nanocomposites were analyzed by various characterization technologies. The photocatalytic capabilities of as-produced materials were then investigated via adsorption and photodegradation of triphenylmethane dyes (TPMs) as crystal violet (CV), basic fuchsine (BF), and malachite green (MG) solution. The results revealed that the removal of Ni-TiO/AC, Ni-TiO/2MAC, Ni-TiO/4MAC, and Ni-TiO/8MAC on TPMs is a very fast process and the removal efficiency can almost reach to about 90% in 10 min, and the catalyst has good cycle stability and is easy to be reused. This work provides a novel, low-cost, and effective way to rationally design and synthesize TiO-based photocatalysts for effective removal of TPMs.