Modi's high ratings are unusual for a global leader three years into a five-year term.
"The honeymoon period for his administration may be over but the public's love affair with current conditions in India is even more intense," the Pew Research Center, which carried out the survey, said in a statement.
Modi's Bharatiya Janata Party-led coalition swept the 2014 general elections, securing the country's biggest parliamentary majority in three decades. The following year, Pew found that 87% of Indians held a favorable opinion of Modi, a fraction lower than the newest poll, which places his popularity at 88%.
But there's a bigger story behind the overwhelmingly positive numbers.
The survey was conducted in February and March, before Modi overhauled the tax system
, replacing a complicated patchwork of local levies with a national goods and services tax that has been blamed for the country's more recent economic slowdown.
The new tax framework replaced more than a dozen federal and state tariffs, duties and fees on nearly everything sold in the country. The idea was to make it simpler for companies to do business across the vast country of 1.3 billion.
But in the short term at least, it has been cited as a major factor behind a drop in India's growth rate
-- now at under 6%, a three year low -- as businesses big and small struggle to adapt to the new system.
The slowdown has also been blamed on another big Modi move -- his shock decision to withdraw high-value bank notes
, equivalent to around 86% of the country's paper cash, in November last year.
At the time, Modi defended the move as a means of preventing wealthier Indians from hoarding cash and avoiding tax.
According to Bruce Stokes, Director of Global Economic Attitudes at the Pew Research Center, the purpose of a poll is to provide numbers and analyzing them brings "personal views" into the issue.
"If we did this survey today, would people feel differently about the economy? I don't know. We'd have to do the survey again to find out. But I would caution you that we did it after demonetization and it doesn't seem to have adversely affected the results," said Stokes.
"If we do it after (the tax overhaul), would that have an adverse effect? I don't know. There's a plausible argument that it might but there's also a plausible argument that it might not," he added.
A total of 2,464 respondents in India were surveyed, which, while a fraction of India's total population, Stokes said was representative in terms of gender, background and education.
The next general election is due in 2019, though a truer test of Modi's popularity is likely to come in forthcoming local elections, held later this month and into December across a number of states, including the Prime Minister's home territory of Gujarat.