The invention discloses a coplanar microstrip antenna with symmetric double arms. The coplanar microstrip antenna comprises a substrate, an impedance matching input transmission line, an L-shaped patch, an inversed L-shaped patch, a left inversed U-shaped patch, a right inversed U-shaped patch, an U-shaped patch, an eye-shaped patch, a left grooved grounding plate and a right grooved grounding plate, wherein the lower end of the impedance matching input transmission line is connected with the bottom end of the base, the upper end of the impedance matching input transmission line is connected with the middle lower end of the U-shaped patch, the left upper end of the impedance matching input transmission line is connected with the right end of the L-shaped patch, the right upper end of the impedance matching input transmission line is connected with the left end of the inversed L-shaped patch, the left upper end of the L-shaped patch is connected with the right lower end of the left inversed U-shaped patch, the right upper end of the inversed L-shaped patch is connected with the left lower end of the right inversed U-shaped patch, the left end of the left grooved grounding plate is connected with the left end of the base, the right end of the right grooved grounding plate is connected with the right end of the base, and the lower ends of left grooved grounding plate and the right grooved grounding plate are connected with the bottom end of the base. The coplanar microstrip antenna has the advantages of wide frequency band, low loss, good radiation characteristic, low cost and small size, and is easy to fabricate and convenient to integrate.