Theoretical and experimental investigations are carried out to determine the influence of the phase matching angle and non-collinear angle on the optical parametric chirped pulse amplification (OPCPA) amplified spectrum of yttrium calcium oxyborate (YCOB) crystal. In theory, through the numerical simulation calculation, it is found that the amplified spectrum of YCOB-OPCPA is sensitive to the phase matching angle and non-collinear angle. When the phase matching angle or non-collinear angle is changed even in a small range, center wavelength drifting and narrowing phenomenon will occur in the gain spectrum. However, when the non-collinear angle is between 2.80° and 2.91°, there is always a phase matching angle that can match the non-collinear angle to satisfy the OPCPA output of more than 80 nm broadband with high power. With the purpose of getting high efficiency and broadband OPCPA output, a method to measure the non-collinear angle accurately based on high accurate CCD is proposed. With this method, the YCOB-OPCPA gain spectrum characteristics based on different non-collinear angles are researched, and the broadband OPCPA gain spectrum is acquired. The experimental results can provide a reference for single-shot pulse OPCPA experiments.