Serum HBV pregenomic RNA (pgRNA), as an important marker of HBV replication activity, has significant potential in virological monitoring and efficacy evaluation. In this study, two highly sensitive HBV pgRNA detection platforms were developed based on catalytic hairpin assembly technology, combined with flow lateral immunochromatography and colloidal gold immunochromatography. The signal amplification achieved by CHA technology avoids the dependence of RT-qPCR on thermal cycling equipment. The experimental results showed that the minimum detection limit of CHA-LFIA was 1 pM, and the minimum detection limit of CHA-GICA was 10 pM. Both CHA-LFIA and CHA-GICA had good specificity and could effectively distinguish between target RNA and non-target sequences. The results of CHA-LFIA and CHA-GICA were highly consistent with those of RT-qPCR, and had the potential for clinical application. This study provides a simple, rapid and innovative solution for the detection of HBV pgRNA, which does not rely on expensive equipment, and can be used for the early diagnosis and treatment monitoring of HBV infection.