Semiconductor saturable absorption mirrors (SESAMs) have become the important components in the compact mode-locking solid-state lasers. we designed a side-pumped folded cavity Nd:YAG solid laser mode-locking with SESAM and got the highest average output power of about 4.7 W. The single pulse has about 85 nJ energy and 55 MHz repeat frequency. The spectrum is measured and the full wavelength at half maximum (FWHM) is about 0.1 nm, and the M2 factor is about 1.2. Significantly, with exactly measurement about the thermal focus length, special cavity can be designed to control the mode radius. Although the laser was pumped by high power LDs (over hundreds watts), but it still has very well beam quality(nearly the diffraction-limited beam). From this work, it get closer towards the high power mode-locking solid laser.