The emergence of parity-time ($mathcal{PT}$) symmetry has greatly enriched our study of symmetry-enabled non-Hermitian physics, but the realization of quantum $mathcal{PT}$-symmetry faces an intrinsic issue of unavoidable symmetry-breaking Langevin noises. Here we construct a quantum pseudo-anti-$% mathcal{PT}$ (pseudo-$mathcal{APT}$) symmetry in a two-mode bosonic system without involving Langevin noises. We show that the pseudo-$mathcal{APT}$ phase transition across the exceptional point yields a transition between different types of quantum squeezing behaviors, textit{i.e.}, the squeezing factor increases exponentially (oscillates periodically) with time in the pseudo-$mathcal{APT}$ symmetric (broken) region. Such dramatic changes of squeezing factors and associated quantum states near the exceptional point are utilized for ultra-precision quantum sensing with divergent sensitivity. These exotic quantum phenomena and sensing applications induced by quantum pseudo-$mathcal{APT}$ symmetry can be experimentally observed in two physical systems: spontaneous wave mixing nonlinear optics and atomic Bose-Einstein condensates.
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