A robust downlink timing synchronization method in an LTE method, comprising the following steps: step 1: a receiving terminal continuously storing time domain signal sequences of M Primary Synchronization Signal, PSS, transmission periods, and recording as: y = y 0 0, y 0 1,..., y 0 N − 1, y 1 0, y 1 1,..., y 1 N − 1,..., y M − 1 0, y M − 1 1,..., y M − 1 N − 1 wherein one PSS transmission period is 5 ms, N is a received data length in every 5 ms, M is the number of the 5 ms periods to be superposed, and M ≥1; step 2: performing narrowband filtering on the time domain signal sequences of the M PSS transmission periods; step 3: performing down-sampling on data obtained after the filtering, and the data obtained after the down-sampling is recorded as: y ̅ = y ̅ 0 0, y ̅ 0 1,..., y ̅ 0 N ̅ − 1, y ̅ 1 0, y ̅ 1 1,..., y ̅ 1 N ̅ − 1,..., y ̅ M − 1 0, y ̅ M − 1 1,..., y ̅ M − 1 N ̅ − 1 wherein y m (·) is received data in the m th 5 ms period after the down-sampling, and N is a data length in every 5 ms after the down-sampling; step 4: performing sliding differential mirror correlation on the down-sampling data of an m th PSS transmission period to obtain a correlation value Ri(m) of an i th instant, wherein m=0, 1, 2,... M-1, the performing time domain sliding differential mirror correlation on the down-sampling data of an m th 5 ms period to obtain a correlation value of an i th instant is: R i m = 1 30 ∑ k = 1 30 r m, i k = 1 30 ∑ k = 1 30 y ̅ m * k + 1 + C y ̅ m k + C y ̅ m * − k + C y ̅ m − k − 1 + C where a superscript * represents complex conjugate, C= i +64/2 is a symmetry center, and k is a summation index; step 5: superposing correlation results to obtain R i = 1 M ∑ m = 0 M − 1 R i m; and step 6: determining whether the superposition result R(i) has an obvious peak interval; if yes, completing capturing the primary synchronization signal, and obtaining timing information according to a position of a maximum correlation peak; otherwise, returning to step 1. step 1: a receiving terminal continuously storing time domain signal sequences of M Primary Synchronization Signal, PSS, transmission periods, and recording as: y = y 0 0, y 0 1,..., y 0 N − 1, y 1 0, y 1 1,..., y 1 N − 1,..., y M − 1 0, y M − 1 1,..., y M − 1 N − 1 wherein one PSS transmission period is 5 ms, N is a received data length in every 5 ms, M is the number of the 5 ms periods to be superposed, and M ≥1; step 2: performing narrowband filtering on the time domain signal sequences of the M PSS transmission periods; step 3: performing down-sampling on data obtained after the filtering, and the data obtained after the down-sampling is recorded as: y ̅ = y ̅ 0 0, y ̅ 0 1,..., y ̅ 0 N ̅ − 1, y ̅ 1 0, y ̅ 1 1,..., y ̅ 1 N ̅ − 1,..., y ̅ M − 1 0, y ̅ M − 1 1,..., y ̅ M − 1 N ̅ − 1 wherein y m (·) is received data in the m th 5 ms period after the down-sampling, and N is a data length in every 5 ms after the down-sampling; step 4: performing sliding differential mirror correlation on the down-sampling data of an m th PSS transmission period to obtain a correlation value Ri(m) of an i th instant, wherein m=0, 1, 2,... M-1, the performing time domain sliding differential mirror correlation on the down-sampling data of an m th 5 ms period to obtain a correlation value of an i th instant is: R i m = 1 30 ∑ k = 1 30 r m, i k = 1 30 ∑ k = 1 30 y ̅ m * k + 1 + C y ̅ m k + C y ̅ m * − k + C y ̅ m − k − 1 + C where a superscript * represents complex conjugate, C= i +64/2 is a symmetry center, and k is a summation index; step 5: superposing correlation results to obtain R i = 1 M ∑ m = 0 M − 1 R i m; and step 6: determining whether the superposition result R(i) has an obvious peak interval; if yes, completing capturing the primary synchronization signal, and obtaining timing information according to a position of a maximum correlation peak; otherwise, returning to step 1.