Polymer　acceptors　for　high-efficiency　all-polymer　solar　cells　(all-PSCs)　are　generally　semicrystalline.　In　this　manuscript,　we　report　an　amorphous　polymer　acceptor,　which　matches　well　with　a　variety　of　polymer　donors　to　produce　efficient　all-PSCs.　The　amorphous　polymer　acceptor　(rr-PBN)　is　a　regiorandom　polymer　consisting　of　alternating　asymmetric　B　＜-　N　bridged　thienylthiazole　(BNTT)　unit　and　pyridine-flanked　diketopyrrolopyrrole　(PyDPP)　unit.　It　is　amorphous　in　thin　film　because　of　its　regiorandom　structure　and　the　large　steric　hindrance.　rr-PBN　shows　deep　LUMO/HOMO　energy　levels　of　-3.71/-5.81　eV,　strong　sunlight　harvesting　capability　and　high　electron　mobility　of　2.20　x　10(-4)　cm(2)　V-1　s(-1).　As　a　polymer　acceptor,　rr-PBN　matches　well　with　three　commercially　available　polymer　donors,　J71,　PTB7-Th,　and　PffBT4T-20D　to　give　excellent　percolating　bicontinuous　network　morphology　in　all-PSCs.　We　propose　that　the　crystallization　of　polymer　donors　governs　the　film-forming　process　and　dominates　the　phase　separation　morphology,　leading　to　good　phase　separation　morphology.　The　all-PSC　devices　all　show　power　conversion　efficiencies　(PCEs)　of　5.2-6.6%.　This　study　provides　a　new　direction　to　design　polymer　acceptors　and　a　novel　approach　to　control　phase　separation　morphology　of　all-PSCs.