Two-dimensional gap plasmonic waveguide employing surface plasmon polaritons is proposed. Transmission characters of 90 degrees sharp bend waveguide, T-shaped splitter and switch based on gap plasmonic waveguide are numerical simulated with finite-difference time-domain method. It is shown that the energy loss of 90 degrees sharp bend waveguide is ohmic losses which are different to radiation losses of dielectric optical waveguide. When the gap width is larger than 40 nm, the transmission of bend waveguide is larger than straight waveguide with the same length. In the T-shaped splitter, when the gap width ratio of two output waveguides is larger than 0.6, the output energy is mainly assigned to the output waveguide which effective index is smaller. The result is different from dielectric optical splitter. The T-shaped switch is off with two input light out of phase and is on with two input light in phase. The plasmonic modes in the above devices beyond the diffraction limit and can be employed in super-large-scale optical integrated circuit.