Blue phase liquid crystals (BPLC) are self-assembled 3D photonic crystals with high dynamic tunability. We review our recent progress on dynamic tuning of BPLC’s photonic band gap, crystal symmetry and orientation by electric field and light. With negative dielectric anisotropy, electrically induced switching between - and -oriented BPI states can be achieved through a transient flow state induced by electro-hydrodynamic instabilities. In dielectrically positive polymer-stabilized BPLCs, applying a DC electric field will induce a stretch of the lattice along the field direction, resulting in a bandgap red-shift of over 200 nm. Such a field-induced stretch can also induce chirped lattice spacing along the field axis in samples fabricated under a different photopolymerization condition, leading to an effective expansion of the photonic bandgap. With chiral azo molecular switch doped in polymer-free BPLCs, reversible lattice dilation and phase transition from simple cubic to body-centered cubic symmetry can be induced by light. These techniques bring about many new possibilities of blue-phase photonic crystals for photonic applications.