The invention discloses a leaded shielding detection device for a 16N monitor, and relates to the technical field of nuclear power station radiation detectors. The device comprises a support, a probe,a temperature sensor, an external interface plug-in, a sleeve, a shielding lead block, and an external cover. The beneficial effects of the scheme are that the device is additionally provided with the shielding lead block at a proper position at an outer side of the probe; the arrangement position of the shielding lead block is determined through the calculation of the position of an NaI crystalin the probe, so as to effectively receive the gamma rays emitted by a steam pipe in a detection process; meanwhile, the device eliminates the impact of a bottom on a measurement environment; the stepped staggered design of the lead block effectively forms circular shielding, and the external cover is added to mainly fix the lead block, and enables the whole device to be an integrated structure; the device in the scheme can effectively improve the reliability of the detection result, guarantees the reasonable and effective operation of the 16N monitor, and achieves the convenient assembly anddisassembly and the beautiful and elegant appearance.