We demonstrate the laser performances of Er-doped YAP crystals with the atom fraction of Er 3+ of 10% pumped by an xenon lamp in the region of 2.7-3 μm. The output mirrors with three different transmissivities are adopted, and the maximum single pulse energies of 1173 mJ @1 Hz, 1284 mJ @5 Hz, 495 mJ @10 Hz, and 104 mJ @20 Hz with the corresponding slope efficiencies of 0.80%, 0.99%, 0.84% and 0.44% are achieved, respectively. Under the conditions of a repetition rate of 5 Hz and output mirror transmission of 15%, the highest laser output energy and laser efficiency can be obtained in the Er∶YAP crystals and the corresponding average output power is 6.42 W, which is about four times the existing best result reported by literatures. In addition, the laser beam quality of the Er∶YAP solid-state laser with different input powers is measured, which decreases with the increase of input power. Moreover, the four laser spectral lines at 2710, 2728, 2795, and 2918 nm are observed. Therefore, the excellent multi-wavelength mid-infrared laser output can be realized with Er∶YAP crystals.