Abstract: The 10 time series of ^239+240Pu specific activity and ²⁴⁰Pu/²³⁹Pu atom ratio in reef and atoll corals in the Pacific Ocean and Atlantic Ocean were analyzed and compared, at the same time discussed its source and its significance to the environment. The results showed that ^239+240Pu in corals mainly came from global fallout and Pacific Proving Grounds (PPG) close-in fallout. As the difference growth environments between shore reefs and atolls, the time series of ^239+240Pu in corals also showed different characteristics. Large-scale atmospheric nuclear weapons test between 1952 and 1958 in the Pacific Proving Grounds made close-in fallout or local input of Pu become the main source of available Pu for corals in seawater. The time series of ^239+240Pu in corals have different time series patterns from that of global fallout Pu. So the time series of ^239+240Pu specific activity in Pacific corals (the main peak time position corresponds to 1954) and in Atlantic corals (the main peak time position corresponds to 1964) have different patterns. Pu in corals maybe indicate the direction of seawater current, El Nio phenomena on a large spatial scale and the fluctuation period of lagoon seawater on a small spatial scale in ocean.