"大量使用标语" can be translated into English as "extensive use of slogans" or "heavy reliance on slogans".
"Extensive use of slogans" emphasizes the widespread or frequent application of slogans.
"Heavy reliance on slogans" highlights a strong dependence or over-emphasis on slogans as a means of communication or promotion.
Both expressions are suitable depending on the context and the intended nuance.