Simultaneous generation of noncollinear red, green, and blue light from a single hexagonally poled lithium tantalate is reported. It results from the frequency self-doubling optical parametric amplification process, a process of second-order harmonic generation cascaded optical parametric amplification in a single-pass setup. The temperature and spectrum detuning characters of each cascaded quasi-phase-matching process are studied. This unique red-green-blue light source has potential applications in laser display and other laser industries.