  The GECAM mission consists of two identical microsatellites (GECAM-A and
GECAM-B). Each satellite is equipped with 25 gamma-ray detectors (GRD) and 8
charged particle detectors (CPD). The main scientific objective of the GECAM
mission is to detect gamma-ray bursts (GRBs) associated with the gravitational
wave events produced by the merging of binary compact stars. After the launch
on Dec. 10, 2020 , we carried out a series of on orbit tests. This paper
introduces the test results of the GECAM-B satellite. According to the
in-flight performance, the energy band for gamma-ray detection of GECAM-B is
from about 7 keV to 3.5 MeV. GECAM-B can achieve prompt localization of GRBs.
For the first time, GECAM-B realized a quasi-real-time transmission of trigger
information using Beidou-3 RDSS. Keywords GECAM, gamma-ray burst, gravitational
wave, GRD, CPD
