Marsh stroked 89 from 83 deliveries after coming in at No. 3, while Maxwell hammered a 46-ball 93 as the pair added 109 runs for the fourth wicket in just nine overs to help Australia post 350 for six in their 50 overs.
In reply, Zimbabwe were bowled out for 152 in 39.3 overs, with Hamilton Masakadza's 70 the only score of note as the hosts crashed to their biggest ever defeat against Australia.
Australia hit a record 15 sixes in their innings, with Marsh and Maxwell accounting for nine of them, as the tourists easily beat their previous best of five in an innings against Zimbabwe.
It was also Australia's highest score in an ODI against Zimbabwe, eclipsing the 344 for seven made in Hobart during a triangular series in January 2004.
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Although Australia started slowly after they were asked to bat first on a sluggish pitch, Aaron Finch and Brad Haddin laid a solid platform with an opening stand of 98.
George Bailey, who was leading Australia in the absence of the injured Michael Clarke, failed to get going, but his dismissal brought Marsh and Maxwell together and the results were spectacular.