Chemical investigation of a marine-derived actinomycete strain Micromonospora sp. FIM05328 isolated from a soil sample collected from the East China Sea, resulted in the discovery of a new 26-membered polyene macrolactam metabolite FW05328-1 (1), together with a known polyene with pyridone ring compound aurodox (2). The structures of compounds 1 and 2 were determined by the detailed analysis of 1D, 2D NMR and HR-TOF-MS data, along with literature data analysis. 1 and 2 exhibited excellent antiproliferative activities against KYSE30, KYSE180 and EC109 human tumour cell lines, but displayed no antibacterial activities against bacteria or fungi were tested.