Abstract: Based on the design principle of neutron multi-sphere spectrometer in this paper, the detector with multi-counter inserted into sphere moderator was machined. The measurement equipment with multi-path of the counter was connected. The dose estimation mode by unfolding of a few channels was adopted under the double-sphere measurement. The neutron field of terrestrial cosmic ray was measured for the double-sphere. The annual dose is about 78 μSv/a at Harbin area. Compared with the results of the multi-sphere spectrometer, the relative deviations of neutron fluence rate and neutron ambient dose equivalent rate for double-sphere are less than 3% and 12%, respectively.