Multistage pain perception is of great significance for surviving the outside harmful stimuli for organisms. In this work, using a sodium alginate biopolymer electrolyte as neurotransmitter layer, a 5×5 array of junctionless transistoris successfully fabricated for pain perception. The device operates well at low voltage (2 V) with a large current on-off ratio (>10⁴) and on-state current (>10 μA). This coplanar-gate array can not only emulate the important functions of synapses, such as excitatory postsynaptic current, paired-pulse facilitation, and dynamic filtering, but also successfully mimic pain-perception and sensitization abilities of the artificial nociceptor network. Furthermore, this work also successfully emulates the multistage spatio-temporal sensitization in the nociceptor network. Construction of this kind of network system provides a new way for the application of the next-generation neuromorphic brain-like system.