The design objectives of code provisions usually lack validations. This study aims to make clear the constitutive relations, capacity gradients and probability assurance of beam-column joints following Chinese seismic code based on pseudo-static tests. Twelve joint specimens are made in 1:1.5 large scale and grouped by fortification levels, exterior - interior locations, and middle – bottom stories. Loadings and measurements at beam ends were transformed to moment-rotation relations of joints; measurements at reinforcements and joint cores helped to confirm the dominance of bending failure and the independence of joints’ strength to locations. Thus, by summarizing the statistic properties of the hysteretic loops and backbone curves, beam hinge models were extracted; by including measurements at different wings and inserting test-unavailable points through regression relations, sample numbers were enlarged; by introducing randomness to earthquake actions, the fragility curves were obtained. Results showed that, the capacity gradients between columns and beams set by code are realized, but gradients between fortification levels aren’t; higher fortification does not help to improve the post-yielding performance; 8° external joints have the highest probability assurance, and then the internal 7° joints.