Back-illuminated 640×1 linear InGaAs detector arrays were fabricated on the In0.78Al0.22As/In0.78Ga0.22As material of N-on-P configuration by the inductively coupled plasma (ICP) etching. The photoelectric characteristics of the detector were investigated. The results indicated that the cutoff-wavelength and peak-wavelength are 2.36 μm and 1.92 μm, respectively, at room temperature. The average value of R0A is 16.0 Ω·cm2 and the quantum efficiency of the peak wavelength reaches to 37.5%. Otherwise, the average peak detectivity of linear detector array reaches to 2.01×1011 cmHz1/2/W, the response nonuniformity is about 8.77% and the defective pixel ratio is 0.6% for 1 ms of integrate time.