Five preservatives,based on different formulas of Ammoniacal copper quaternary（ACQ）,were selected to treat bamboo to evaluate their performance of decay and leaching resistance.The result showed that ACQ-B and ACQ-D were the best for decay resistance while ACQ-C exhibited poor decay resistance,especially at low retention levels.It was observed that adding（NH4）2HPO4 to the typical ACQ preservative increased the toxicity to white rot（Potyporus versicolor Fr.）,but had little influence to brown rot（Poria placenta Fr.）.The five preservatives also demonstrated different performances in keeping the active ingredients in bamboo.ACQ-B and ACQ-B-P showed a higher preservative fixation rate while the others illustrated lower fixation rates.