Planar reflectarrays are receiving more and more attentions since they were proposed a few decades ago due to their many advantages, such as flat and low-profile structures, low manufacturing cost, and relatively high efficiency and so on -. Although a few analytical formulas can reveal their operating principles, practical designs of planar reflectarrays are actually a quite complicated and troublesome process. A lot of factors should be taken into consideration, for example, there are reflection phase, reflection efficiency, beamwidth, and bandwidth just only for element itself, and several other factors for the whole arrays . Metamaterials with controllable permittivity and permeability over an interesting frequency band attract efforts and attentions of many researchers , in spite that there are some controversies about them . Planar gradient index (GRIN) lens  is a typical one among many applications of metamaterials, which can be made by a series of split ring resonators (SRR) with gradually increasing refractive index , or other structures - . The possibility to replace traditional curved lens by the planar GRIN lens is reported, since as it is known that the former is costly and much difficult to fabricate . In , it is employed to realize beam steering or focusing to improve electrical performances of horn antennas. Moreover, since the particles operate in non-resonant mode in the GRIN lens, the loss inherent in metamaterials is also quite small. In this paper, a type of novel reflectarray based on the GRIN lens is proposed. Basic idea about the new reflectarray is carefully addressed in next section, and then initial simulated results are given in the following part.