Nonclassical optical frequency combs find tremendous utility in quantum information and high-precision quantum measurement. The characteristics of a type-I synchronously pumped optical parametric oscillator with the TEM01 transverse mode below threshold are investigated and a squeezing of 0.7 dB for an optical frequency comb squeezed light field with the TEM01 transverse mode is obtained under the pump power of 130 mW. This work has a promising application in three-dimensional space-time measurement.