We study the phenomenology of Peccei-Quinn invariant Supersymmetric Standard Models. The motivations for the class of models are briefly reviewed. And the effective interactions of the axion supermultiplet are carefully examined with emphasis on distinction among three seemingly similar but different quantities on the axion-gauge-gauge supermultiplet interaction, the 1PI amplitude, Wilsonian coupling, and PQ anomaly coefficient. Then an important conclusion is derived for the dominant interaction of axino at the energy scale between the mass of the heaviest PQ-charged and gauge-charged matter and the PQ scale, which has direct implications for cosmology. Applying the result to the cosmological production of axino in specific axion models, the reheat temperature bound and dark matter properties are studied. After that, the Next-to-Minimal Supersymmetric Standard Model (NMSSM) with the PQ symmetry is investigated in the light of the 125 GeV Higgs data. The minimal PQ-NMSSM turns out to be severely constrained by the invisible decay channel from Higgs to lightest neutralino pair. Nevertheless, in small $ \tan \beta \lesssim 2 $ region, there exists plausible parameter space by the aid of the PQ sector to evade the constraints from dark matter, alleviating the fine-tuning in the Higgs mass. This parameter space may also enhance the diphoton signal rate up to a factor of 1.5 for the heavy doublet Higgs mass $ m_H \lesssim 480 $. Also it should be commented that the general PQ-NMSSM with non-zero supersymmetric mass term of singlino can evade these restrictions. Finally, the generic collider signature of the minimal PQ-NMSSM at the LHC is studied.